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TR-4 (TR4, Telefunken-Rechner 4),
was a West-German digital general purpose mainframe computer developed since 1956 and manufactured and shipped since 1962 by Telefunken in Backnang and later in Konstanz. Developers include Gudrun Beyer, Wolfgang Händler [1], Hans-Otto Leilich, Kuno Radius, Egbert Ulbrich, Eike Jessen and Heinz Voigt [2]. 36 TR-4 computers were manufactured and delivered mostly to West-German universities and public authorities and their associated data centers.
TR-4 CPU Rack with Teletype [3]


The computer had a word size of 52 bits, consisting of 48 data bits, 2 type bits (00 - floating point, 38 bit normalized mantissa, 01 - integer/fixed point, 10 - opcode 2x24 bit, 11 - 8 six bit text characters) and 2 bit checksum (Dreierprobe), checksum errors causing interrupts. ALU and registers were build in discrete transistor technique running at 2 MHz, main memory consists of up to 28,672 words of core memory and 4096 words of semiconductor memory. Auxiliary storage were magnetic tapes, punched tapes and cards, and disk drives. The hard-wired micro-programmable computer took 9 and 40 cycles for fixed and floating point addition respectively, and about 60 cycles (30µs) for a multiplication. ALU, instruction-, memory- and I/O units were able to work in parallel, controlled by a time-sharing operating system, which also incorporates the machine instruction translators SUSA (TR4-Assembler) and TEXAS (Telefunken Externcode Assembler). Algol, Fortran and COBOL compiler were available.

Four Register Units [4] - VR (Verteiler register) distribution register
  • ALU (Rechenwerk)
    HR Help-Register
    MD multiplicand register
    AC Accumulator
    ÜB Carry register
    MQ Multiplier register
  • Memory Unit (Speicher)
    Sp1 Memory 1
    Sp2 Memory 2
    FSp Fixed Memory
    X Index Memory
    • (256 registers in core)
  • I/O-Unit (E/A-Werk)
    I/O registers
  • Instruction Unit (Befehlswerk)
    BA Address
    BR Instruction register
    BZ Instruction counter
    MS Microprogram Control Unit


In 1968, the TR4 was superseded by the ten times faster TR 440, which already had the first ball-based mouse named Rollkugel [5].

Chess Programs

External Links


  1. ^ Erlangen Classification System - Wikipedia.de (German)
  2. ^ Eike Jessen, Dieter Michel, Hans-Jürgen Siegert, Heinz Voigt (2008). AEG-Telefunken TR 440: Unternehmensstrategie, Markterfolg und Nachfolger. Informatik - Forschung und Entwicklung, Vol. 22, No. 4
  3. ^ TELEFUNKEN TR4 am Leibniz-Rechenzentrum 1965 by Gerd Sapper (German, English)
  4. ^ TR-4_Brochure_Apr60.pdf, pp. 2
  5. ^ Telefunken Rollkugel ~ oldmouse.com

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